The railway train system as we know it today is said to have evolved from a system Welsh coal miners devised to move coal out of a mine shaft at the beginning of the industrial revolution. The miners first placed coal into wooden-wheeled wagons and rolled them on wooden planks placed over the muddy ground up and out of a sloping mine shaft. The wooden wheels and planks were soon replaced by ones made of iron and a mule was added to pull the wagon. The iron planks eventually gave way to an iron rail, the iron wheels were attached to ever larger carriages and the mule replaced by an engine in a locomotive. Despite the various advances, the fundamental concept of steel wheel on steel rails persists through today. Even magnetic levitation based train systems maintain a continuous rail as both guide and support for the force field.
The basic railway train system employs the following set of essential components: (1) steel wheels, (2) steel rails, (3) railroad bridges, (4) roadbeds, (5) a propulsion source, and (6) rail cars. The steel wheels, which are attached to the passenger car, run on the steel rails. This method produces a low coefficient of friction and has been a very economical method of transportation. Railroad bridges are devices used to span open spaces where it is not possible to have a continuous roadbed. Importantly, the railroad bridge must carry its own weight and that of the train. The roadbed (in the form of the ground or the railroad bridge) is an accumulation of mass that holds the rails formed as tracks in place and distributes the forces generated by the passing train. Propulsion in the form of a locomotive or motor contained within the passenger cars must also be present to push or pull the train along. Then there must be rail cars, such as passenger cars or freight cars, which are compartments that function to safely transport passengers or freight.
Although the basic railway train system is partially responsible for transforming human civilization from the industrial revolution to modern times, it is not without its problems. In the present day, a basic railway train system is extremely costly to construct. The cost of building new urban rail systems has risen beyond reach for most municipalities and regional planners. For example, the cost for Los Angeles Blue Line escalated from $194 million to $890 million, while Buffalo's $24 million tab ballooned to $552 million. As of December of 2011 the estimated cost for the construction of light rail ranged from $130 to $150 million dollars per mile. These extremely high costs are primarily due to the costs of land acquisition and disruptions to existing infrastructure.
There is a need, therefore, for a mass transportation system that operates without reliance on steel wheels riding on rails.